WindowManager Eating up Vast CPU Resources

Hello! I stumbled upon your post when doing a Google search for the exact same issue you describe above. I've been living with this ever since the original OS update that triggered it, and subsequent updates have not resolved the issue. WindowManager goes to 100% every time I try to do anything with a window, whether simply moving it or opening a menu.

I *finally* resolved the issue today and thought I would post my solution here just in case you are still having the same problem.

I never use Mission Control but, on a whim, I decided to investigate to see if that might have something to do with it. As it turns out, I had 950+ desktops going! I did not create any of these additional desktops so I have no idea where they came from, but closing all of them completely resolved my issue and WindowManager is barely registering any CPU usage in Activity Monitor now.

Hope this helps!

Part 1 of 2

Use the Activity Monitor application and make sure to use View >> View All Processes 

What process or processes are using the Most CPU.

Often times - the issue maybe not a single Process  alone but a combination of Processes

Also, when the computer is using so much CPU / Memory - it can be a indicator of a Lack Of Empty Spaces on the Drive.

In which case, the CPU and Memory usage would become Much More because it is searching for Empty Space to save all the Changes the user is performing.

Also, depending on the number of  Open Tabs in your Browser, they can also affect CPU / Memory Usage.

Part 2 of 2

User wrote " Just upgraded to Ventura 13.3.1. "

The current version has long pasted that version and is currently now on Version 13.5.1

Links below specific to Updates and the Security of this computer

Keep your Mac up to date - Apple Support (CA)

Apple security releases - Apple Support (CA)

I you use Chrome, try uninstalling it completely, including removing all the configuration files. I have I M1 Max and it reduced my windowserver process usage from ca. 45% to about 15 - 20%. Here are detailed instructions: https://chromeisbad.com/

If you need a Chromium based browser Opera and Vivaldi are good alternatives.

YES YES YES YES YES YES!!!! Thanks @Holben. I had 200 desktops that appeared out of nowhere on Mission Control but closing them has solved the issue (hold option key to keep the "x" up so you can close them quicker!).

You have done the Lord's work with your selfless reply!

[Edited by Moderator]

Are you using Settings>Desktop & Dock>Stage Manager? If so, try turning it off.